The term thoracic outlet syndromes (TOSs) encompasses several diverse clinical disorders (one of dubious validity) involving blood vessels, nerve fibers, or both at various points as they traverse the cervicoaxillary canal. The blood vessels affected may be arteries or veins, subclavian or axillary; the neural structures involved are various portions of the brachial plexus.<sup>90 Wilbourn A.J., Porter J.M. Thoracic outlet syndromes Spine 1988 ;  2 : 597-626

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The first classification of the TOSs was provided by Peet and co-workers<sup>58 Peet P.M., Henriksen M.D., Anderson T.P. Thoracic outlet syndrome: Evaluation of a therapeutic exercise program Mayo Clin Proc 1956 ;  31 : 281-287

Cliccare qui per andare alla sezione Riferimenti</sup> in 1956. It currently has little relevance because it was based on the presumed bony or dynamic factors responsible for the injury, rather than on the particular structure(s) injured. The latter has been the focus of more recent classifications.<sup>20 Dawson D.M., Hallett M., Wilbourn A.J. Thoracic outlet-syndromes Entrapment Neuropathy Philadelphia: Lippincott-Raven (1998).  228-251

Cliccare qui per andare alla sezione Riferimenti, 92 Wilbourn A.J. Thoracic outlet syndrome syllabus, Course D: Controversies in Entrapment Neuropathies American Association of Electromyography and Electrodiagnosis Rochester: Minnesota (1984).  28-38

Cliccare qui per andare alla sezione Riferimenti</sup> (Table 1). Thus, the TOSs can be subdivided into vascular or neural disorders or both, depending on what specific structures within the cervicoaxillary canal are compromised.

This presentation concerns the three subgroups of TOS in which the brachial plexus is involved, either alone (true neurologic TOS) or with concomitant vascular compromise at times (traumatic TOS; disputed TOS). Those subgroups of TOS that solely affect blood vessels (arterial TOS; venous TOS) are not discussed. The anatomy of the region, being common to all types of TOS, is reviewed first.